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Functional role of muscle reflexes for force generation in the decerebrate walking cat

2000· article· en· W1984989267 on OpenAlexaff
Richard B. Stein, John E. Misiaszek, K. G. Pearson

Bibliographic record

VenueThe Journal of Physiology · 2000
Typearticle
Languageen
FieldEngineering
TopicMuscle activation and electromyography studies
Canadian institutionsUniversity of Alberta
FundersMedical Research Council
KeywordsAnkleTriceps surae muscleTreadmillAnatomyAchilles tendonElectromyographyReflexMuscle spindlePhysical medicine and rehabilitationMedicineTendonPhysical therapyAfferentAnesthesia

Abstract

fetched live from OpenAlex

To quantify the importance of reflexes due to muscle length changes in generating force during walking, we studied high decerebrate cats that walked on a treadmill. One leg was denervated except for the triceps surae and a few other selected muscles. The triceps surae muscles are ankle extensor muscles that attach to the Achilles' tendon which was cut and connected to a muscle puller. In some steps the EMG activity triggered the puller to move the muscle through the pattern of length changes that are normally produced by ankle movements in intact cats walking over ground (simulated walking). In other steps the muscles were held isometrically. The EMG and force produced during the two types of steps were compared. On average about 50 % more EMG was generated during the E2 part of the simulated stance phase in the triceps surae muscles, but not in other muscles studied. Force was increased significantly over the entire stance phase by about 20 %, when muscle stretches simulating walking were applied. However, during much of the stance phase the triceps surae muscles are shortening and so would produce less force. The effect of shortening was assessed in control experiments in which these muscles were stimulated at a constant frequency, either isometrically or during simulated walking movements. By combining data from the walking and control experiments, we estimate that about 35 % of the force produced in the cat ankle extensors during stance is produced by reflexes due to muscle length changes. Other sensory inputs may also contribute to force production, but the total reflex contribution will vary under different conditions of speed, length, loading, task difficulty, etc. Since a substantial percentage of the force in the stance phase of walking is normally produced by muscle reflexes, this force can be continuously adjusted up or down, if the muscles receive extra stretch or unloading during a particular step cycle.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.621
Threshold uncertainty score0.115

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.017
GPT teacher head0.231
Teacher spread0.215 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one teacher head, not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designBench or experimental
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations93
Published2000
Admission routes1
Has abstractyes

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